The present invention in general relates to transport vehicles and trucks and, in particular, to a linear travel device for a self-propelled articulated vehicle having two separate vehicle modules for carrying a load thereon.
The vast majority of conventional transporting vehicles in utilization today comprise tractor-trailer combinations in which an independent driving tractor module is engaged with a separate container-trailer which is pivotally attached thereto, usually by a fifth wheel connection supported on the rear of the tractor unit. With such an arrangement, the driving or powered wheels are limited to the interchangeable tractor unit, leaving the container or trailer portion with no independent power drive means of its own. Often, the greatest amount of weight distribution is concentrated onto the wheels supporting the container, and not the tractor, which creates maneuverability problems when the tractor's drive wheels are mired down in slick, muddy and/or rough terrain. Additionally, maneuverability problems become increasingly important in this "load pulling" arrangement, especially when the wheels of either separate component, the tractor, or the trailer, gets stuck in such mud, or becomes ineffective due to entrapment in loose earth, sand, bog, snow, or piles of litter, often encountered in refuse dumps and the like. Similarly, such a "load pull" arrangement for the vehicle and the load hampers the ability to "walk out" of tire track ruts and soft terrain due to the locating of the power drive means on only the forward tractor power drive wheels.
Also associated with the more conventional tractor-trailer arrangement for transporting containerized loads, are the problems of poor maneuverability in turns arising out of the often enormous length of the container height and trailer itself which, through its length, remains unarticulated and rigid. Most typical of these problems are the substantially large turning radii of such vehicles, as well as the inescapable problem involved with turning relatively sharp corners wherein the tractor unit must be drawn out as far as possible into the turn so as to keep the container-trailer unit from slicing across the corner as the turn is executed. The wear-and-tear on concrete curbing, as well as the tires on the container-trailer portion of the vehicle, all too often attest to the punishment handed out by such a vehicle. So, too, do the many accidents which occur when a driver in the tractor unit must draw the vehicle out as close to the oncoming traffic as possible, so as to negotiate many ordinary, not to mention, sharp turns.
The overwhelming vast majority of such tractor-trailer vehicles for hauling containerized goods, such as semi-trailer trucks having containerized dump or refuse hauling means associated therewith, encounter several other problems due to their type of construction. Almost all of these vehicles rely upon steering through the use of conventional Ackerman steering mechanisms in which the two or more front wheels of the front cab portion can be swiveled into place to enter a change of course for the vehicle. The vast amount of mechanical cooperating elements, pumps, reservoirs, and mechanisms involved with conventional steering techniques on such containerized transport vehicles increase the power consumption and through such a conventional steer front axle with its associated turning wheels. Unless increased power loss is developed through the addition of a power steering unit, drivers operating such conventional type transport vehicles often find the steering and overall handling of such a massive vehicle overwhelming.
Similarly, the lack of power drive means and overall steering control on the rear portion of the conventional vehicle, that is the container-trailer portion, increases the potential for out-of-control situations in which, for example, the overall vehicle is more prone to jackknifing.
Another drawback arising out of the use of conventional type tractor-trailer or semi-trailer type vehicles, arises under the concern paid today to Federal and State regulations on maximum loads and weight distribution requirements directed towards the truck industry. As is well known, weight distribution and load limits are often calculated on the basis of weight per axle and/or weight per power driven axle. The limitations imposed by conventional tractor-trailer vehicles as well as the inability to selectively distribute the weight of a containerized load amount often reduces the legal load carrying limit and requires the utilization of more transportation vehicles and greater power and fuel consumption in order to effectuate delivery of desired loads.
Inherent with the problems listed above, several articulated vehicles have been devised which, to a degree, offset the limitations discussed. As an alternative to the conventional tractor-trailer or semi-trailer truck configuration utilized in commerce today, vehicles such as those disclosed in Kamner, U.S. Pat. No. 3,515,235 have been devised. While steering on this particular reference is dependent upon conventional Ackerman steering means, to a degree, reduction in turning radius and improvement in maneuverability can nonetheless be obtained. Similarly, articulated vehicles, as those disclosed in Robinson et al., U.S. Pat. No. 2,933,143; Starkey U.S. Pat. No. 2,271,808; Lindell, U.S. Pat. No. 3,771,241, and McGee, U.S. Pat. No. 2,834,480 have been develped to offset the conventional difficulties outlined above. But it should be realized that few, if any, of these references offer the structural characteristics of an articulated vehicle formed by two separate vehicle modules, each having its own power drive means. Similarly, few, if any, of these references disclose the particular utilization of a single container means distributed over and supported by both of the vehicle modules to afford selective weight distribution and the ability to obtain particular load displacement characteristics of the container when such a vehicle negotiates turns.
It is thus an object of the present invention to provide a self-propelled articulated vehicle comprising two separate articulated vehicle modules which can walk out of tire track ruts, crawl, or inch through adverse soft terrain, and avoid miring down in mud, loose earth, sand, snow, refuse dumps, etc. through the use of independent module drives which can be synchronized. Similarly, it is an object of the present invention to be more maneuverable and have a sharper turning radius with easier steering than conventional truck transport apparatus.
It is also an object of the present invention to provide a viable alternative to conventional Ackerman steering systems by utilizing a simpler steering mechanism to provide more efficient steering without the need for mechanical constructions inherent with the Ackerman system. At the same time, such a construction reduces the power loss, friction, and cumbersome characteristics of conventional steering.
It is additionally an object of the present invention to enable greater payloads to be carried than conventional vehicles through enabling maximum legal loading on all axles of the vehicle by selection. At the same time, it is an object to attain these results on a vehicle transporting container means in which the payload of the vehicle is loaded.
Further, it is an object of the present invention to provide an articulated vehicle comprising two vehicle modules which impart a desired displacement of a container supported by both modules so as to enable inter-changeability of specific containers, describing specific displacements, without the need for adjusting the basic two-module articulated vehicle. At the same time, it is an object to provide a self-propelled articulated vehicle having all of these improved features as an alternative to conventional transporting apparatus, which has the additional feature of minimizing the likelihood of lack of control of the vehicle by the driver, thus reducing the possibility of jackknifing. These and other objects of the invention will become apparent through the present disclosure.